The present invention relates to belt associated power transmission apparatus and more particularly to an improved power transmission sheave of the multi-grooved rim type capable of association with any one of several preselected types of multi-groove sheaves having a like number of grooves and a method of manufacturing such an improved sheave.
Various types of multi-grooved metal sheaves of cast iron, die cast, and formed steel are known in the power transmission art, these different multi-groove sheave types each having different properties for different power transmission functions with each multi-groove sheave type having specific types of belt sets to be associated therewith in a power transmission assembly. Among the several differing physical properties of the varying multi-groove sheave types are the material used, the hub and bushing associated with the sheave, the sheave diameter size, the angle of slope of the grooved side wall of each groove in the sheave, the top and bottom widths of each groove, the depth of each groove, the spacing between the center lines extending through the bottom widths of adjacent grooves and the number of grooves involved. These properties have been important factors in arriving at the different and numerous commercial multi-groove sheave types, including such well known multi-groove sheaves commonly known in the power transmission industry as the "A", "B", "5V", "A/B Combination" and the "SPB" multi-groove sheaves, each of which types is associated with an endless power transmission belt set of a specific type. As will be discussed more fully hereinafter, these several multi-groove sheave types, as well as the particular endless belt set associated therewith, differ from each other in their above discussed physical properties. Accordingly, it has been common practice to select a specifically designs multi-groove sheave and a set of endless belts for association with each such multi-groove sheave type and to insure that both drive and driven multi-groove sheaves are of a compatible, similar type. It has been generally recognized that departure from such practices in the past could lead to undesirable problems in power transmission efficiencies and to power losses, poor belt set performance, poor belt set body and belt set cord wear and undesirable belt set groove bottoming with some of the associated undesirable problems aforediscussed concomitant with such undesirable belt set bottoming.
The present invention, recognizing the past undesirable problems associated with proper multi-groove sheave and belt set selection from the many types of belt sets and multi-groove sheaves commercially available and also recognizing the undesirable problems associated with the comparatively extensive stocking and possible improper belt set and multi-groove sheave matching, provides a unique and novel multi-groove sheave structure and method of manufacturing such sheave structure which greatly simplifies multi-groove sheave stocking and selection, assuring commonality and compatibility of usage with any one of the several above recited types of multi-groove sheaves and the previously associated belt sets therefor, over a broad horsepower range without incurring the above discussed undesirable problems which could arise through possible mismatch. In addition, the present invention provides a unique multi-groove sheave which allows for greatly increased belt set life without belt set bottoming and with increased heat dissipation between belt set and multi-groove sheave. Moreover, the present invention recognizes and resolves a need for providing a multi-groove sheave type which includes recognized critical properties accompanied by increased top groove width and increased groove depth in the grooves of the set, a preselected angle of groove wall slope, preselected top and bottom groove widths and a preselected spacing of adjacent grooves of the set. These recognized properties serve to allow the usage of any one of several belt sets specifically selected for multi-groove sheaves of varying preselected types, each of which sheave types is generally well known for use in the power transmission art in a comparatively more restricted environment. Further, the present invention provides a unique multi-groove sheave with preselected spacing between the centers of adjacent bottom groove widths to enhance efficient multi-groove sheave operation with comparatively minimum misalignment of the belt sets between drive and driven multi-groove sheaves.